Agricultural sprayers typically have long spray booms with groups of spray nozzles that are selectively controlled by respective control valves, each of which is individually actuated to permit transmission or termination of liquid to the spray nozzles of the group. Termination of liquid to one or more groups of spray nozzles is commonly necessary, for example, near the ends of fields so as to prevent spraying on non-crop vegetation or the like. The control valves of such spraying systems are commonly mounted in ganged or manifold side-by-side aligned relationship with respect to each other and remote from the spray nozzles they control, with liquid being directed through the line of control valves. In addition, each control valve is customarily provided with a valve element which is movable between open and closed positions to selectively control the flow of liquid to the spray nozzles of the respective group. Previously, the mounting and coupling of such control valves has been cumbersome, required complicated fixtures, and has not enabled easy disassembly or uncoupling of individual control valves for repair or replacement. For example, it is known in the art to couple a plurality of the control valves in a side-by-side fluid communicating array with a plurality of elongated rods which extend through the valve bodies to retain the control valves in an assembled relationship. Not only is such mounting relatively complicated, but to remove and repair an individual control valve, it is necessary to disassemble the entire array. Moreover, it can be difficult to precisely align and orient the array of control valves with respect to each other. Known control valves also have inlet and outlet configurations which do not lend themselves to easy interconnection or which are not compatible for effective sealing with different types of supply and output line couplings or adapters. In addition, to mount a ganged assembly of control valves for a spraying system, it has often been necessary to utilize bracketry which requires relatively precise positioning of mounting holes. Furthermore, while it is desirable to use plastic components to reduce weight and cost, heretofore such plastic elements have been susceptible to breakage or overstressing when coupled to each other or to liquid supply and return lines.
Still further performance problems can occur when such ganged control valves are employed to regulate flow through outlets carrying a multiplicity of spray nozzles which are adapted to provide different flow rates and spray performances. For example, adjusting one set of spray nozzles to provide a desired flow rate therethrough can increase or decrease pressure within the spraying system which can alter the flow rate through other nozzles, either increasing or decreasing the chemical application beyond the preferred limits. In addition, while it is known for control valves to be operable for directing fluid to a bypass line during periods in which liquid communication to the nozzles has been terminated and for controlling the bypass flow rate to correspond with that of the flow rate of the nozzles in use, adjusting the bypass flow rate heretofore has been tedious and time consuming. Moreover, control valves for use with a bypass line, referred to as three-way valves, require additional components, and have not been easily convertible for use as a two-way valve in spray systems which do not include a bypass line.